The above-referenced parent patent, which is incorporated herein by reference, discloses and claims a method of forming a silicate gel by polymerization reaction which exhibits intumescence upon application of heat. The present application relates to more specific applications of this method and to the fabrication of products or materials produced thereby.
The parent patent discusses various prior art processes and materials involving the hardening of aqueous alkali metal silicate compositions to form a gel or solid product, and the distinctions and advantages of the method of the parent patent. It has been found through further experimentation that certain, more specific parameters within the scope of the method more generally disclosed and claimed in the parent patent provide enhanced properties of the end products, especially as employed in particular applications. Also, further useful products and applications utilizing such methods have been devised, and are disclosed herein.
Accordingly, it is a principal object of the present invention to provide useful articles and materials comprising silicate gels formed by polymerization reaction, and novel methods for the production of such articles.
More specific objects within the scope of the foregoing are to provide:
1. structural materials, e.g., sheets suitable for use as wall board, having mechanical properties similar to conventional gypsum board, but of lower density, higher strength and higher degree of fire protection;
2. very low density ceramic foam materials for use in sheets or blocks as bulk insulation in construction applications;
3. a fireproof article including an encapsulated gel material between a pair of liners or substrates useful as a protective barrier layer in packaging and building systems;
4. a vitreous material produced by heating the intumesced ceramic foam to a temperature at which it begins to soften or melt; and
5. ceramic foam materials using silicic acid (silica gel) as a principal additive ingredient and intumesced with microwave heat.
Other objects will in part be obvious and will in part appear hereinafter.